The incident occurred at around 4.50pm on Tuesday when the maroon and white single decker bus was travelling along Musselburgh Road, Dalkeith, near the Thornybank roundabout.

A stone then struck the bus, which was thrown by youths standing on a bridge. This caused one of the large windows to smash, resulting in £800 of damage.

Officers are now investigating and are appealing for any information regarding this incident.

Police Sergeant Michele Lindsay said: “This was a particularly irresponsible and reckless act carried out, which could have potentially injured one or more of the passengers travelling on the bus at the time.

“We are keen to speak to anyone who was in the area around 4.50pm on Tuesday or anyone who has information regarding this crime so that we can quickly trace the person’s responsible.

“We will be carrying out patrols in the area to provide reassurance, deter further incidents and deal with any crimes detected. Anyone with information that can help us identify the persons responsible is asked to come forward.”

Those with information can contact Police Scotland on 101 or alternatively, the charity Crimestoppers on 0800 555 111.